Cyclohexenone compounds, their preparation and their use for controlling undesirable plant growth

ABSTRACT

Cyclohexenone compounds of the formula ##STR1## where R 1  is alkyl of 1 to 4 carbon atoms, alkenyl or alkynyl of 3 or 4 carbon atoms, haloalkenyl of 3 or 4 carbon atoms and 1 to 3 halogen substituents, or is thenyl which is unsubstituted or substituted by halo and/or alkyl, R 2  is alkyl of 1 to 4 carbon atoms, and R 3  is formyl, a radical of the general formula R 4  XCHXR 5 , where X is oxygen or sulfur, and R 4  and R 5  are identical or different alkyl, or together denote alkylene of 1 to 4 carbon atoms and which is unsubstituted or substituted by alkyl, alkoxy, alkylthio, hydroxy, halogen, cyano or N,N-dialkylamino, have a good herbicidal action preferably on species from the grass family.

This application is a continuation of application Ser. No. 07/545,764,filed on Jun. 29, 1990, now abandoned, which is a continuation of Ser.No. 07/281,999, filed Dec. 9, 1988, now abandoned.

The present invention relates to cyclohexenone compounds, processes fortheir preparation and herbicides which contain these compounds as activeingredients.

It is known that cyclohexenone compounds can be used for controllingundesirable grasses in broad-leaved crops (German Laid-Open ApplicationDOS 2,439,104). Furthermore, German Laid-Open Applications DOS 3,248,554and DOS 3,329,017 disclose that cyclohexen-1-one compounds which carry apara-substituted phenyl radical in the 5-position control gramineousweeds in wheat.

We have found that cyclohexenone compounds of the formula I ##STR2##where R¹ is alkyl of 1 to 4 carbon atoms, alkenyl or alkynyl of 3 or 4carbon atoms, haloalkenyl having 3 or 4 carbon atoms and 1 to 3 halogensubstituents or thienyl which is unsubstituted or monosubstituted,disubstituted or trisubstituted by halogen and/or C₁ -C₄ -alkyl, R² isalkyl of 1 to 4 carbon atoms and R³ is formyl or a radical of thegeneral formula R⁴ XCHXR⁵, where X is O or S and R⁴ and R⁵ are identicalor different alkyl radicals or together form alkylene of 1 to 4 carbonatoms and which may additionally be substituted by C₁ -C₄ -alkyl, C₁ -C₄-alkoxy, C₁ -C₄ -alkylthio, hydroxyl, halogen, cyano or C₁ -C₄-N,N-dialkylamino, and their biologically acceptable salts with alkalimetal, alkaline earth metal and ammonium ions and their esters with C₁-C₁₀ -carboxylic acids and inorganic acids have a good herbicidalaction, preferably against species from the grass family (Gramineae).They are tolerated and therefore selective in broad-leaved crops and inmonocotyledon plants which do not belong to the Gramineae. Somecompounds also show selective behavior in crops of Gramineae, forexample wheat, barley or rice, in the sense that they control undesirable grasses without significantly damaging the useful crops.

Formula I gives only one of the possible tautomeric forms; there arealso many other possible forms, all of which are intended to be embracedby the general formula I, as shown below. ##STR3## The novelcyclohexenone compounds are evidently acids, ie. they can form simplereaction products of biologically acceptable acids, such as salts ofalkali metal or alkaline earth metal compounds or esters. Thecorresponding salts or esters are also embraced by the invention.

In formula I, R¹ is, for example, ethyl, n-propyl, allyl, preferablychloroalkenyl, such as (E)-3-chloro-2-propenyl, 2-chloro-2-propenyl or3,3,2-tri-chloro-2-propenyl, and also, for example, propargyl,2-butynyl, (E)-2-butenyl and 5-chloro-2-thienyl.

In formula I, R² is methyl, ethyl, n-propyl, isopropyl, n-butyl,sec-butyl, isobutyl or tert-butyl.

In formula I, R³ is formyl, dialkoxymethyl of 3 to 9 carbon atoms, forexample dimethoxymethyl, diethoxymethyl, dipropoxymethyl,dibutoxymethyl, di-(2-methoxyethoxy)-methyl,di-(2-ethylthioethoxy)-methyl, di-(2-chloroethoxy)-methyl,di-(2,2,2-trichloroethoxy)-methyl, di-(3-bromopropoxy)-methyl,di-(2,2,3,3,4,4,4-heptafluorobutoxy)-methyl ordi-(3-methoxy-1-methylpropoxy)-methyl, dialkylthiomethyl of 3 to 9carbon atoms, for example di-(methylthio)-methyl, di-(ethylthio)-methyl,di-(propylthio)-methyl, di-(butylthio)-methyl,di-(2-ethoxyethylthio)-methyl, di-(2-ethylthioethylthio)methyl,di-(3-chloropropylthio)-methyl, di-(2-cyanoethylthio)-methyl ordi-(2-N,N-dimethylaminoethylthio)-methyl, dioxolanyl of 3 to 9 carbonatoms, for example 4-ethyl1,3-dioxolan-2-yl,4,5-dimethyl-1,3-dioxolan-2-yl, 4,4-dimethyl-1,3-dioxolan-2-yl,4,4,5-trimethyl-1,3-dioxolan-2-yl, 4-chloromethyl-1,3-dioxolan-2-yl,4-methylthio-ethyl-1,3-dioxolan-2-yl or4-hydroxymethyl-1,3-dioxolan-2-yl, dithiolanyl of 3 to 9 carbon atoms,for example 1,3-di-thiolan-2-yl or 4-methyl-1,3-dithiolan-2-yl,oxothiolanyl of 3 to 9 carbon atoms, for example 1,3-oxo-thiolan-2-yl,dioxanyl of 3 to 9 carbon atoms, for example 4-methyl-1,3-dioxan-2-yl,5,5-dimethyl-1,3-dioxan-2-yl, 4,4-di-methyl-1,3-dioxan-2-yl,4,4,6-trimethyl-1,3-dioxan-2-yl or5-methoxymethyl-5-methyl-1,3-dioxan-2-yl, or dithianyl of 3 to 9 carbonatoms, for example 1,3-dithian-2-yl.

The oxime ethers of the formula Ib are obtained from the acylderivatives of formula II in a two-stage process. The first stepcomprises the chemoselective formation of the acetal or thioacetal,which is obtained by processes known from the literature (an overview isgiven by C. Ferri in Reaktionen der organischen Synthese, page 426 etseq. and page 491 (1978)). In the second step, this acetal/thioacetal isreacted with an appropriate hydroxylamine salt R¹ ONH₃ Y, where Y is anyanion, to give the oxime ether of the formula Ib. ##STR4##

This reaction is advantageously carried out in the heterogeneous phasein a diluent at an adequate temperature above 0° C. and below theboiling point of the reaction mixture, in the presence of a base.Examples of suitable bases are carbonates, bicarbonates, acetates,alcoholates, hydroxides or oxides of alkali or alkaline earth metals, inparticular of sodium, potassium, magnesium or calcium. Organic bases,such as pyridine or tertiary amines, can also be used.

The reaction takes place particularly readily at a pH of from 2 to 9, inparticular from 4.5 to 5.5. The pH is advantageously obtained by addingan acetate buffer, for example sodium acetate or potassium acetate, or amixture of the two salts. Alkali metal acetates are added, for example,in amounts of from 0.5 to 2 moles, based on the ammonium compound of theformula R¹ O--NH₃ Y.

Examples of suitable solvents are dimethyl sulfoxide, alcohols, such asmethanol, ethanol or isopropanol, benzene, hydrocarbons andchlorohydrocarbons, such as chloroform, dichloroethane, hexane orcyclohexane, esters, such as ethyl acetate, and ethers, such as dioxaneor tetrahydrofuran.

The reaction is complete after a few hours, after which the reactionproduct can be isolated by evaporating down the mixture, adding waterand extracting with a nonpolar solvent, such as methylene chloride, anddistilling off the solvent under reduced pressure.

Compounds of the formula I can also be obtained by reactingcorresponding compounds of the formula II with the appropriate freehydroxylamine R¹ O--NH₂ in a diluent at from 0° C. to the boiling pointof the reaction mixture, in particular from 15° to 70° C. If necessary,the hydroxylamine can be used in the form of an aqueous solution.

Suitable solvents for this reaction are, for example, alcohols, such asmethanol, ethanol, isopropanol or cyclohexanol, hydrocarbons andchlorohydrocarbons, such as hexane, cyclohexane, methylene chloride,toluene or dichloroethane, esters, such as ethyl acetate, nitriles, suchas acetonitrile, and cyclic esters, such as tetrahydrofuran.

The compounds of the formula Ia where R³ is formyl are obtained, forexample, by hydrolyzing the acetal esters III (R³ =dialkoxymethyl) bymeans of an aqueous alkali metal hydroxide solution, for example sodiumhydroxide solution or potassium hydroxide solution, at from 0° to 100°C., preferably at room temperature. On subsequent acidification to pH1-5 with a conventional acid, for example hydrochloric acid, sulfuricacid, phosphoric acid, acetic acid, oxalic acid or formic acid, thedesired aldehyde is formed with simultaneous decarboxylation andcleavage of the acetal, and is, if required, isolated by extraction.Suitable extracting here are all organic solvents which are not misciblewith water, for example toluene, dichloromethane or ethyl acetate.

Compounds of the formula Ia can also be obtained by cleavage of theacetals and thioacetals of the formula The conventional processes aredocumented in detail Th. W. Greene Protective Groups in OrganicSynthesis, pages 115-138 (1981).

EXAMPLE 15-(4-dimethoxymethylphenyl)-2-(1-ethoxyiminobutyl)-4-hydroxycyclohex-2-en-1-one

2.5 g of ethoxyamine, 2.1 g of sodium bicarbonate and 100 ml of methanolare added to 8.4 g of2-butyryl-5-(4-dimethoxymethylphenyl)-3-hydroxycyclohex-2-en-1-one andthe mixture is stirred for 10 hours at room temperature. After themixture has been evaporated down, the residue is partitioned inmethylene chloride/water, and the organic phase is separated off, driedand evaporated down. 7.5 g of5-(4-dimethoxymethylphenyl)-2-(1-ethoxyiminobutyl)-3-hydroxycyclohex-2-en-1-one(compound No. 19 in the Table below) remain: ##STR5##

EXAMPLE 22-(1-Ethoxyiminobutyl)-5-(4-formylphenyl)-3-hydroxycyclohex-2-en-1-one

2.0 g of the compound No. 19 (Example 1) were treated with a mixture of3.5 g of silica gel (70-270 mesh), 5 ml of dichloromethane and 0.35 g of10% strength oxalic acid for 15 hours at room temperature. The mixturewas filtered, the residue was washed with dichloromethane and thefiltrate was evaporated down. 1.5 g of2-(1-ethoxyiminobutyl)-5-(4-formylphenyl)-3-hydroxycyclo-hex-2-en-1-oneremain as a solid of melting point 81°-82° C. (compound No. 8). ##STR6##

The compounds listed in the table below can be prepared from suitableintermediates, if necessary after slight adaptation of the aboveexamples; they are expected to have a similar action. A typicalselection of compounds (characterized by physical data) was prepared andinvestigated for biological activity.

                                      TABLE                                       __________________________________________________________________________     ##STR7##                                                   (I)               Comp.                                     m.p. [°C.] or                                                          characteristic .sup.1 H-NMR                                                   data                                no.  R.sup.3          R.sup.2                                                                            R.sup.1        [δ ppm]                       __________________________________________________________________________    1    CHO              C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              1.17(t), 1.33(t), 2.97(q),                                                    4.13(q),                                                                      10.0(s)                             2    CHO              C.sub.2 H.sub.5                                                                    n-C.sub.3 H.sub.7                                                                            1.0(t), 2.96(t), 3.10(q),                                                     4.03(t),                                                                      10.0(s)                             3    CHO              C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                                                           1.18(t), 2.97(t), 4.58(d),                                                    10.01(s)                            4    CHO              C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                                                            1.17(t), 2.92(q), 4.55(d),                                                    6.12(m),                                                                      6.36(d), 10.0(s)                    5    CHO              C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                                                                      1.18(t), 1.78(d), 2.97(q),                                                    4.47(d),                                                                      10.0(s)                             6    CHO              C.sub.2 H.sub.5                                                                     ##STR8##                                                                                     ##STR9##                           7    CHO              C.sub.2 H.sub.5                                                                     ##STR10##                                         8    CHO              n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              81-82                               9    CHO              n-C.sub.3 H.sub.7                                                                  n-C.sub.3 H.sub.7                                                                            0.99(t); 4.03(t); 10.01(s)                                                    66-68                               10   CHO              n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                                                           1.01(t); 5.96(m); 10.01(s)                                                    63-64                               11   CHO              n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                                                            0.99(t); 6.11(m); 6.36(d)           12   CHO              n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                            13   CHO              n-C.sub.3 H.sub.7                                                                   ##STR11##                                                                                    ##STR12##                          14   CHO              n-C.sub.3 H.sub.7                                                                   ##STR13##     68-70                               15   CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              1.19(t), 1.33(t), 2.97(q),                                                    3.34(s),                                                                      4.15(q), 5.37(s)                    16   CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                                                           1.18(t), 2.95(q), 3.32(s),                                                    4.55(d),                                                                      5.36(dd)                            17   CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                                                            1.16(t), 2.91(q), 3.33(s),                                                    4.53(d),                                                                      5.39(s)                             18   CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                                                                      1.17(t), 1.77(d), 2.96(q),                                                    3.33(s),                                                                      4.48(d), 5.38(s)                    19   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              0.98(t); 3.33(s); 4.10(s)           20   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                                                           0.99(t), 2.95(t), 3.33(s),                                                    4.55(d),                                                                      5.35(dd), 5.36(s)                   21   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                                                            0.99(t), 3.33(s), 4.53(d),                                                    5.38(s)                             22   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                                                                      1.0(t), 1.78(d), 3.34(s),                                                     5.39(s)                             23   CH(OC.sub.2 H.sub.5).sub.2                                                                     C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              2.97(q), 4.15(q), 5.5(s)            24   CH(OC.sub.2 H.sub.5).sub.2                                                                     C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                 25   CH(OC.sub.2 H.sub.5).sub.2                                                                     C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                  26   CH(OC.sub.2 H.sub.5).sub.2                                                                     C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            27   CH(OC.sub.2 H.sub.5).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              0.99(t), 1.23(t), 1.32(t),                                                    4.12(q),                                                                      5.5(s)                              28   CH(OC.sub.2 H.sub.5).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                 29   CH(OC.sub.2 H.sub.5).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                  30   CH(OC.sub.2 H.sub.5).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                            31   CH(OC.sub.4 H.sub.9).sub.2                                                                     C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    32   CH(OC.sub.4 H.sub.9).sub.2                                                                     C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                 33   CH(OC.sub.4 H.sub.9).sub.2                                                                     C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                  34   CH(OC.sub.4 H.sub.9).sub.2                                                                     C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            35   CH(OC.sub.4 H.sub.9).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    36   CH(OC.sub.4 H.sub.9).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                 37   CH(OC.sub.4 H.sub.9).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                  38   CH(OC.sub.4 H.sub.9).sub.2                                                                     n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                            39   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  n-C.sub.3 H.sub.7                                                                            0.99(t), 3.34(s), 4.04(t),                                                    5.37(s)                             40   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                   ##STR14##     0.97(t), 3.34(s), 4.66(d),                                                    5.34(s)                             41   CHO              n-C.sub.3 H.sub.7                                                                  5-chloro-2-thenyl                                  42   CHO              C.sub.2 H.sub.5                                                                    5-chloro-2-thenyl                                  43   CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  5-chloro-2-thenyl                                  44   CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    5-chloro-2-thenyl                                  45   CH(OCH.sub.2 CH.sub.2 OCH.sub.3).sub.2                                                         n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    46   CH(OCH.sub.2 CH.sub.2 OCH.sub.3).sub.2                                                         C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            47   CH(OCH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.3).sub.2                                                n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    48   CH(OCH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.3).sub.2                                                C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                 49   CH(OCH.sub.2 CH.sub.2 Cl).sub.2                                                                n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    50   CH(OCH.sub.2 CH.sub.2 Cl).sub.2                                                                n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                 51   CH(OCH.sub.2 CH.sub.2 Cl).sub.2                                                                n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                  52   CH(OCH.sub.2 CH.sub.2 Cl).sub.2                                                                C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    53   CH(OCH.sub.2 CH.sub.2 Cl).sub.2                                                                C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            54   CH(OCH.sub.2 CCl.sub.3).sub.2                                                                  C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            55   CH(OCH.sub.2 CH.sub.2 CH.sub.2 Br).sub.2                                                       n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    56   CH(OCH.sub.2 CH.sub.2 CH.sub.2 Br).sub.2                                                       C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                  57   CH(OCH.sub.2 CF.sub.2 CF.sub.2 CF.sub.3).sub.2                                                 n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                  58   CH(OCH.sub.2 CF.sub.2 CF.sub.2 CF.sub.3).sub.2                                                 C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            59   CH(OCH(CH.sub.3)CH.sub.2 OCH.sub.3).sub.2                                                      C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    60   CH(SCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              0.99(t), 1.32(t), 2.1(s),                                                     4.79(s)                             61   CH(SCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                                                                      0.99(t), 2.1(t), 4.47(d),                                                     4.79(s)                             62   CH(SCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                                                            0.98(t), 2.11(s), 4.56(d),                                                    4.78(s)                             63   CH(SCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              69-71                               64   CH(SCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    n-C.sub.3 H.sub.7                                  65   CH(SCH.sub.2 CH.sub.3).sub.2                                                                   C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              1.17(t, 3H), 1.23(t, 6H),                                                     1.34(t, 3H),                                                                  4.1(q, 2H), 4.92(s, 1H)             66   CH(SCH.sub.2 CH.sub.3).sub.2                                                                   n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              1.0(t, 3H), 1.26(t, 6H),                                                      1.36(t, 3H),                                                                  1.61("6", 2H), 4.16(q, 2H)          67   CH(SCH.sub.2 CH.sub.2 CH.sub.3).sub.2                                                          n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    68   CH(SCH.sub.2 CH.sub.2 CH.sub.3).sub.2                                                          C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                                                                      0.95(t), 1.14(t), 4.47(d),                                                    4.86(s)                             69   CH(SCH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3).sub.2                                                 n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    70   CH(SCH.sub.2 CH.sub.2 CH.sub.2 CH.sub.3).sub.2                                                 n-C.sub.3 H.sub.7                                                                   ##STR15##                                         71   CH(SCH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.3).sub.2                                                n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                            72   CH(SCH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.3).sub.2                                                C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                  73   CH(SCH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.3).sub.2                                                C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            74   CH(SCH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.3).sub.2                                                n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                 75   CH(SCH.sub.2 CH.sub.2 CH.sub.2 Cl).sub.2                                                       n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    76   CH(SCH.sub.2 CH.sub.2 CH.sub.2 Cl).sub.2                                                       C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                 77   CH(SCH.sub.2 CH.sub.2 CN).sub.2                                                                n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                  78   CH(SCH.sub.2 CH.sub.2 CN).sub.2                                                                C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            79   CH[SCH.sub.2 CH.sub.2 N(CH.sub.3).sub.2 ].sub.2                                                n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    80   CH[SCH.sub.2 CH.sub.2 N(CH.sub.3).sub.2 ].sub.2                                                C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    81   1,3-dioxan-2-yl  n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              94-95                               82   1,3-dioxan-2-yl  C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                  83   4,4-dimethyl-1,3-dioxan-2-yl                                                                   n-C.sub.3 H.sub.7                                                                  n-C.sub.3 H.sub.7                                  84   4,4-dimethyl-1,3-dioxan-2-yl                                                                   C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                 85   4-chloromethyl-1,3-dioxan-2-yl                                                                 n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    86   4-chloromethyl-1,3-dioxan-2-yl                                                                 n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                            87   4-chloromethyl-1,3-dioxan-2-yl                                                                 C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    88   4-methylthioethyl-1,3-dioxan-2-yl                                                              n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    89   4-hydroxymethyl-1,3-dioxan-2-yl                                                                n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    90   4-hydroxymethyl-1,3-dioxan-2-yl                                                                C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    91   1,3-dithiolan-2-yl                                                                             n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              0.99(t, 3H), 1.34(t, 3H),                                                     1.61(m, 2H),                                                                  4.12(g, 2H), 5.66(s, 1H)            92   1,3-dithiolan-2-yl                                                                             n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                                                           1.01(t, 3H), 1.62(m, 2H),                                                     4.58(d, 2H),                                                                  5.67(s, 1H)                         93   1,3-dithiolan-2-yl                                                                             C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                                                                      97-98                               94   1,3-dithiolan-2-yl                                                                             C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                                                            72-75                               95   4-methyl-1,3-dithiolan-2-yl                                                                    C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    96   1,3-oxothiolan-2-yl                                                                            n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    97   1,3-dithiolan-2-yl                                                                             n-C.sub.3 H.sub.7                                                                   ##STR16##                                         98   1,3-dithiolan-2-yl                                                                             n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCH.sub.3                            99   5,5-dimethyl-1,3-dioxan-2-yl                                                                   n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              94-95                               100  5,5-dimethyl-1,3-dioxan-2-yl                                                                   n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                                                            99-100                              101  1,3-dioxan-2-yl  n-C.sub.3 H.sub.7                                                                  CH.sub.2CHCH.sub.2                                 102  1,3-dioxan-2-yl  C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                  103  1,3-dioxan-2-yl  C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                            104  4,4,6-trimethyl-1,3-dioxan-2-yl                                                                n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    105  4,4,6-trimethyl-1,3-dioxan-2-yl                                                                C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                    106  5-methoxymethyl-5-methyl-1,3-                                                                  n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                         dioxan-2-yl                                                              107  1,3-dithian-2-yl n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                                                              1.0(t), 1.33(t), 4.11(q),                                                     5.17(s)                             108  1,3-dithian-2-yl n-C.sub.3 H.sub.7                                                                  (E)CH.sub.2CHCHCl                                                                            1.0(t), 4.52(d), 5.18(s)            109  1,3-dithian-2-yl C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                                                           78-81                               110  1,3-dithian-2-yl C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCH.sub.3                                                                      121-122                             111  CH(OCH.sub.3).sub.2 Na.sup.+  salt                                                             n-C.sub.3 H.sub.7                                                                  C.sub.2 H.sub.5                                    112  1,3-dithiolan-2-yl                                                                             C.sub.2 H.sub.5                                                                    CH.sub.2CHCH.sub.2                                                                           65-68                               113  1,3-dithiolan-2-yl                                                                             C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              84-87                               114  1,3-dithian-2-yl C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              143-45                              115  1,3-dithian-2-yl C.sub.2 H.sub.5                                                                    (E)CH.sub.2CHCHCl                                                                            111-14                              116  CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    n-C.sub.3 H.sub.7                                  117  CH(OCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                     ##STR17##                                                                                    ##STR18##                          118  CH(OCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                   ##STR19##                                                                                    ##STR20##                          119  CH(SCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    CH.sub.2 CHCH.sub.2                                                                          1.2(t, 3H), 2.11(s, 6H),                                                      4.59(d, 2H),                                                                  4.8(s, 1H)                          120  CH(SCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    CH.sub.2 CHCHCH.sub.3                                                                        1.17(t, 3H), 1.79(d, 3H),                                                     2.12(s, 6H),                                                                  4.79(s, 1H)                         121  CH(SCH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                    CH.sub.2 CHCHCl                                                                              1.18(t, 3H), 2.12(s, 6H),                                                     4.56(d, 2H),                                                                  4.79(s, 1H)                         122  CH(SCH.sub.3).sub.2                                                                            n-C.sub.3 H.sub.7                                                                  CH.sub.2 CHCH.sub.2                                                                          0.98(t, 3H), 2.12(s, 6H),                                                     4.56(d, 2H),                                                                  4.77(s, 1H), 5.87-6.08(m, 1H)       123  1,3-dioxan-2-yl  n-C.sub.3 H.sub.7                                                                  CH.sub.2 CHCHCH.sub.3                                                                        84-85                               124  1,3-dioxan-2-yl  n-C.sub.3 H.sub.7                                                                  CH.sub.2 CHCHCl                                                                              78-80                               125  1,3-dioxan-2-yl  n-C.sub.3 H.sub.7                                                                  CH.sub.2 CHCHCH.sub.3                                                                        108-110                             126  5,5-dimethyl-1,3-dioxan-2-yl                                                                   C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                              115-116                             __________________________________________________________________________

The herbicidal agents may be applied pre- or postemergence. If certaincrop plants tolerate the active ingredients less well, applicationtechniques may be used in which the herbicidal agents are sprayed fromsuitable equipment in such a manner that the leaves of sensitive cropplants are if possible not touched, and the agents reach the soil or theunwanted plants growing beneath the crop plants (post-directed, lay-bytreatment).

The application rates depend on the objective to be achieved, the timeof the year, the plants to be combated and their growth stage, and arefrom 0.01 to 3.0, preferably 0.05 to 1.0, kg/ha.

The action of the active ingredients of the formula I on the growth ofplants is illustrated in greenhouse experiments.

The vessels employed were plastic flowerpots having a volume of 300 cm³and filled with a sandy loam containing about 3.0% humus. The seeds ofthe test plants were sown separately, according to species.

For the preemergence treatment, the formulated active ingredients werethen immediately applied to the soil surface. They were suspended oremulsified in water as vehicle and sprayed through finely distributingnozzles. The application rate was 0.5 kg/ha.

After the agents had been applied, the vessels were lightlysprinkler-irrigated to induce germination and growth. The vessels werethen covered with transparent plastic hoods until the plants had takenroot. This cover ensured uniform germination of the test plants, insofaras this was not impaired by the active ingredients.

For the postemergence treatment, the plants were grown to a height offrom 3 to 15 cm, depending on growth form, before being treated. Forthis treatment, either plants which had been sown in the pots and grownthere were selected, or they were cultivated separately as seedlings andtransplanted to the pots a few days before being treated. Theapplication rates were 0.06, 0.125 and 0.25 kg/ha. No covers were placedon the vessels in this treatment method.

The pots were set up in the greenhouse, species from warmer climates inwarmer areas (20° to 35° C.) and species from moderate climates at 10°to 25° C. The experiments were run for from 2 to 4 weeks. During thistime the plants were tended and their reactions to the varioustreatments assessed.

The assessment scale was 0 to 100, 100 denoting nonemergence or completedestruction of at least the visible plant parts, and 0 denoting nodamage or normal growth.

The plants used in the greenhouse experiments belonged to the followingspecies:

    ______________________________________                                        Abbreviation                                                                            Botanical name   Common name                                        ______________________________________                                        AVEFA     Avena fatua      wild oats                                          ALOMY     Alopecurus myosuroides                                                                         blackgrass                                         BROIN     Bromus inermis   smooth broome                                      DIGSA     Digitaria sanguinalis                                                                          large crabgrass                                    LOLMU     Lolium multiflorum                                                                             annual ryegrass                                    MEDSA     Medicago sativa  alfalfa                                            SETIT     Setaria italica  foxtail millet                                     SETVI     Setaria viridis  green foxtail                                      SINAL     Sinapis alba     white mustard                                      TRZAS     Triticum aestivum                                                                              wheat                                              TRZAW     Triticum aestivum                                                                              wheat                                              ZEAMX     Zea mays         Indian corn                                        ______________________________________                                    

Compounds nos. 8, 111 and 19 are suitable for combating grassyvegetation on postemergence application of 0.25 kg/ha. Broadleavedcrops, for example alfalfa, are not damaged. The novel activeingredients have a selective herbicidal action (Table 1).

Compound no. 8 may be used postemergence for combating unwanted grassesin wheat. Damage to the crop plants is slight, if any at all (Table 2).

Compounds nos. 8 and 19, when applied preeemergence at 0.5 kg/ha, have astrong herbicidal action on grassy plants; mustard, an example of abroadleaved species, remains undamaged (Table 3).

Compounds nos. 3 (Table 4) and 4 (Table 5) also combat unwanted grasses.Damage to wheat plants is extremely slight, if any at all. Compoundsnos. 5 and 17 (Table 6) also combat unwanted grassy plants, withoutdamaging alfalfa, as an example of a broadleaved crop.

                                      TABLE 1                                     __________________________________________________________________________    Herbicidal action on unwanted grassy plants and tolerance by a crop on        postemergence application of 0.25 kg/ha in the greenhouse                      ##STR21##                                                                    Comp. no.                                                                           R.sup.3                                                                              X MEDSA                                                                              AVEFA                                                                              BROIN                                                                              LOLMU                                                                              ZEAMX*                                     __________________________________________________________________________     8    CHO    H 0    100  95   100  100                                        111   CH(OCH.sub.3).sub.2                                                                  Na                                                                              0    100  98   98   98                                          19   CH(OCH.sub.3).sub.2                                                                  H 0    100  98   100  100                                        __________________________________________________________________________     *as volunteer corn                                                       

                  TABLE 2                                                         ______________________________________                                        Herbicidal action on unwanted grassy plants and tolerance                     by a crop on postemergence application in the greenhouse                       ##STR22##                                                                                         Test plants and damage (%)                               Comp. no.    kg/ha   TRZAS*   ALOMY  AVEFA                                    ______________________________________                                        8            0.06    5        98     95                                       ______________________________________                                         *Schirokko variety                                                       

                  TABLE 3                                                         ______________________________________                                        Herbicidal action on unwanted                                                 grassy plants and tolerance by a broadleaved unwanted plant                   on preemergence application of 0.5 kg/ha in the greenhouse                     ##STR23##                                                                                     Test                                                                          plants and damage (%)                                        Comp. no. R.sup.3      SINAL     LOLMU                                        ______________________________________                                         8        CHO          0         100                                          19        CH(OCH.sub.3).sub.2                                                                        0         100                                          ______________________________________                                    

Examples illustrating the control of unwanted grassy plants andtolerance by a crop on postemergence application of 0.125 kg/ha in thegreenhouse

                                      TABLE 4                                     __________________________________________________________________________     ##STR24##                                                                    Comp. no.                                                                           R.sub.1 R.sub.2                                                                          R.sub.3                                                                           TRZAS                                                                              LOLMU                                                                              DIGSA                                          __________________________________________________________________________    3     CH.sub.2 CHCH.sub.2                                                                   C.sub.2 H.sub.5                                                                  4-CHO                                                                             10   100  95                                             __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________     ##STR25##                                                                    Comp. no.                                                                           R.sub.1    R.sub.2                                                                          R.sub.3                                                                           TRZAS                                                                              DIGSA                                                                              SETIT                                       __________________________________________________________________________    4     (E)CH.sub.2 CHCHCl                                                                       C.sub.2 H.sub.5                                                                  4-CHO                                                                             0    95   100                                         __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________     ##STR26##                                                                    Comp. no.                                                                           R.sub.1     R.sub.2                                                                          R.sub.3 MEDSA                                                                              LOLMU                                                                              DIGSA                                                                              SETVI                             __________________________________________________________________________     5    (E)CH.sub.2 CHCHCH.sub.3                                                                  C.sub.2 H.sub.5                                                                  4CHO    0    100  100  100                               17    (E)CH.sub.2 CHCHCl                                                                        C.sub.2 H.sub.5                                                                  4CH(OCH.sub.3).sub.2                                                                  0    100   98  100                               __________________________________________________________________________

In view of the spectrum of weeds that can be combated, the tolerance ofthe active ingredients by crop plants or the desired influence of theirgrowth, and in view of the numerous application methods possible, thecompounds according to the invention may be used in a large number ofcrop plants. Examples are given below:

    ______________________________________                                        Botanical name      Common name                                               ______________________________________                                        Allium cepa         onions                                                    Ananas comosus      pineapples                                                Arachis hypogaea    peanuts (groundnuts)                                      Asparagus officinalis                                                                             asparagus                                                 Avena sativa        oats                                                      Beta vulgaris spp. altissima                                                                      sugarbeets                                                Beta vulgaris spp. rapa                                                                           fodder beets                                              Beta vulgaris spp. esculenta                                                                      table beets, red beets                                    Brassica napus var. napus                                                                         rapeseed                                                  Brassica napus var. napobrassica                                                                  swedes                                                    Brassica napus var. rapa                                                                          turnips                                                   Brassica rapa var. silvestris                                                 Camellia sinensis   tea plants                                                Carthamus tinctorius                                                                              safflower                                                 Carya illinoinensis pecan trees                                               Citrus limon        lemons                                                    Citrus maxima       grapefruits                                               Citrus reticulata   mandarins                                                 Citrus sinensis     orange trees                                              Coffea arabica (Coffea canephora,                                                                 coffee plants                                             Coffea liberica)                                                              Cucumis melo        melons                                                    Cucumis sativus     cucumbers                                                 Cynodon dactylon    Bermudagrass                                              Daucus carota       carrots                                                   Elais guineensis    oil palms                                                 Fragaria vesca      strawberries                                              Glycine max         soybeans                                                  Gossypium hirsutum  cotton                                                    (Gossypium arboreum,                                                          Gossypium herbaceum,                                                          Gossypium vitifolium)                                                         Helianthus annuus   sunflowers                                                Helianthus tuberosus                                                                              Jerusalem artichoke                                       Hevea brasiliensis  rubber plants                                             Hordeum vulgare     barley                                                    Humulus lupulus     hops                                                      Ipomoea batatas     sweet potatoes                                            Juglans regia       walnut trees                                              Lactuca sativa      lettuce                                                   Lens culinaris      lentils                                                   Linum usitatissimum flax                                                      Lycopersicon lycopersicum                                                                         tomatoes                                                  Malus spp.          apple trees                                               Manihot esculenta   cassava                                                   Medicago sativa     alfalfa (lucerne)                                         Mentha piperita     peppermint                                                Musa spp.           banana plants                                             Nicotiana tabacum (N. rustica)                                                                    tobacco                                                   Olea europaea       olive trees                                               Oryza sativa        rice                                                      Panicum miliaceum   millet                                                    Phaseolus lunatus   limabeans                                                 Phaseolus mungo     mungbeans                                                 Phaseolus vulgaris  snapbeans, green beans,                                                       dry beans                                                 Pennisetum glaucum  pearl millet                                              Petroselinum crispum                                                                              parsley                                                   spp. tuberosum                                                                Picea abies         Norway spruce                                             Ables alba          fir trees                                                 Pinus spp.          pine trees                                                Pisum sativum       English peas                                              Prunus avium        cherry trees                                              Prunus domestica    plum trees                                                Prunus dulcis       almond trees                                              Prunus persica      peach trees                                               Pyrus communis      pear trees                                                Ribes sylvestre     redcurrants                                               Ribes uva-crispa    gooseberries                                              Ricinus communis    castor-oil plants                                         Saccharum officinarum                                                                             sugar cane                                                Secale cereale      rye                                                       Sesamum indicum     sesame                                                    Solanum tuberosum   Irish potatoes                                            Sorghum bicolor (s. vulgare)                                                                      sorghum                                                   Sorghum dochna      sorgo                                                     Spinacia oleracea   spinach                                                   Theobroma cacao     cacao plants                                              Trifolium pratense  red clover                                                Triticum aestivum   wheat                                                     Vaccinium corymbosum                                                                              blueberries                                               Vaccinium vitis-idaea                                                                             cranberries                                               Vicia faba          tick beans                                                Vigna sinensis (V. unguiculata)                                                                   cow peas                                                  Vitis vinifera      grapes                                                    Zea mays            Indian corn, maize                                        ______________________________________                                    

To increase the spectrum of action and to achieve synergistic effects,the active ingredients of the formula I may be mixed with each other, ormixed and applied together with numerous representatives of otherherbicidal or growth-regulating active ingredient groups. Examples ofsuitable components are diazines, 4H-3,1-benzoxazine derivatives,benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates,thiolcarbamates, halocarboxylic acids, triazines, amides, ureas,diphenyl ethers, cyclohexenones, triazinones, uracils, benzofuranderivatives, quinolinecarboxylic acids, (hetero)-aryloxyphenoxypropionicacids, their salts, esters and amides, etc.

It may also be useful to apply the active ingredients of the formula I,either alone or in combination with other herbicides, in admixture withother crop protection agents, e.g., agents for combating pests orphytopathogenic fungi or bacteria. The compounds may also be mixed withsolutions of mineral salts used to remedy nutritional or trace elementdeficiencies. Non-phytotoxic oils and oil concentrates may also beadded.

We claim:
 1. A cyclohexenone compound of the formula I ##STR27## where R¹ is alkyl of 1 to 4 carbon atoms, alkenyl or alkynyl of 3 or 4 carbon atoms, haloalkenyl of 3 or 4 carbon atoms and 1 to 3 halogen substituents, or is thenyl which is unsubstituted or mono-, di- or trisubstituted by halo and/or C₁ -C₄ -alkyl, R² is alkyl of 1 to 4 carbon atoms, and R³ is formyl, a radical of the general formula R⁴ XCHXR⁵, where X is oxygen or sulfur, and R⁴ and R⁵ are identical or different alkyl, or together denote alkylene of 1 to 4 carbon atoms and which is unsubstituted or substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, C₁ -C₄ -alkylthio, hydroxy, halogen, cyano or C₁ -C₄ -dialkylamino, and their biologically active salts with alkali metal, alkaline earth metal and ammonium ions and esters thereof with C₁ -C₁₀ -carboxylic acids or inorganic acids, and wherein the R₃ is in the 4-position.
 2. A herbicidal composition containing conventional auxiliaries and a herbicidally effective amount of a cyclohexenone compound of the formula I as set forth in claim
 1. 3. A process for combating the growth of unwanted plants, wherein the unwanted plants and/or the area to be kept free from unwanted plant growth is treated with a herbicidally effective amount of a cyclohexenone compound of the formula I as set forth in claim
 1. 4. A cyclohexenone compound of the formula I as defined in claim 1, wherein R³ is formyl, R¹ is ethyl and R² is n-propyl.
 5. A process for combating the growth of unwanted plants that are located among winter wheat plants which comprises treating the unwanted plants and/or the area to be kept free from unwanted plants in winter wheat with a herbicidally effective amount of the cyclohexenone compound of claim
 4. 